1 Terry: So where are we?2 {shot of St Paul's Cathedral through a smoky sky}3 Jane Goodall: London, 1940.3 Terry: Seriously?4 Terry: Of all the times and places in the world, why would a time machine drop us here?4 Jane Goodall: Have you even heard of Dr Who?

Seriously, London is the centre of the biggest time vortex in the universe. At least in spatial coordinates.

And since we're talking about time travel, we have to mention the time coordinate as well. In which case, London during World War II
is the centre of the biggest time vortex in the entire space-time continuum.